For an electron, with n = 3 has only one radial node. The orbital angular momentum of the electron will be :

For an electron, with n = 3 has only one radial node. The orbital angular momentum of the electron will be $\sqrt{2}\frac{h}{2\pi }$.

Number of radial nodes $=n-1-1=1$

Since, $\mathrm{n}=3. \therefore 1=1$

Orbital angular momentum  $=\sqrt{1(1+1)}\frac{h}{2\pi }=\sqrt{2}\frac{h}{2\pi }$

Hence, the option C is correct.